Sounds like a wiring or sender unit problem. Ground wire at sender unit, see if it stays steady. If it still jumps around, wiring/gauge problem. If it stays steady, sender unit should be replaced. Good idea to do an oil pressure test as well.
If you have 10 lbs of oil pressure per 1000 rpms, your fine.
one day my 1988 jeep cherokee loredos rpms wouldnt come down i looked at the linkage and it was not accelerated so i reved the motor a little more and then the rpms came back down to normal but when i try to use the passing gear i have no response i have changed the kick down cable, the tps, the plunger next to the tps what else could it be?
I have the same problem with my 1994 ford gt mustang 5.0 just got it to.
loping is when your engine raises and lowers rpms on its own without touching the throttle
Since you didn't mention what kind of problems or what type of engine this is or the year it was made, we really don't have much to go on. You can edit your question or perhaps go to a local parts store and ask them. We really DO need more information in order to help you.
maybe your rpms gauge is broken.get it looked at by a professional
The spark plug gap can cause the RPMs to fluctuate, while idling. The more probable cause of the fluctuating RPMs is a bad camshaft.
If a 1995 Mazda 626 Manual Transmission has the rpms jumping up and down when stopped and the temperature gauge runs hot all the time, it is possible that the engine has a cracked block. When the block is cracked, the engine will not build up enough compression to stay running and will not hold coolant long enough to keep the engine cool.
mass air flow sensor
Probably a worn out engine.
If you have 10 lbs of oil pressure per 1000 rpms, your fine.
Probably a matter of where the engine's power band is set out, or you may simply be bogging the engine down at lower speeds. Try downshifting and keeping your RPMs up a little.
It's probably either a vacuum leak or a problem with the EGR valve.
check engine mounts
because the engine needs to have a 20 seconds RPMs
it could be a range of things. it could be overheating, gas gauge is low, or your rpms are running too high.
When you are shifting gears, your RPMs will go down because your clutch is being pressed. If your RPMs don't go back up when you release your clutch, you should see a mechanic.